1. HCAL Trigger Primitive Generation in Upgrade Simulation
Edmund Berry, Chris Tully
Princeton University

2. Outline Presenting a first draft of HCAL TPG for upgrade simulation
Goals
Trigger primitives description
Storage classes for current simulation
Storage classes for upgrade simulation
Trigger primitive generators description
Algorithm for current simulation
Algorithm for upgrade simulation
Usage
Plans for the future
HCAL Upgrade Meeting

3. Goals We start by using Jeremy Mans' SLHC CMSSW_2_2_5 release:
oftware
Create a new class of “upgrade” HCAL trigger primitive
Like current HCAL trigger primitives, it should contain compressed et information
Should also contain “isolation” compressed et information and more fine-grain information
Create a new “upgrade” TPG (edm::Producer)
Information common to the “upgrade” trigger primitives and the current trigger primitives should be generated, stored, and accessed in the same way, wherever possible
Linearization scheme in default CMSSW uses LUTs that do not extend to the depth segmentation used in SLHC simulation. Must use a different linearization scheme for HB/HE.
HCAL Upgrade Meeting

4. Current HCAL TP in CMSSW
HcalTriggerPrimitiveDigi
Identified by an HcalTrigTowerDetId
Contains multiple HcalTriggerPrimitiveSamples with bit-wise information
An HcalTriggerPrimitiveSamples has:
8 bits of “compressed et”
1 bit of “fine grain” energy information
HcalSLHCTriggerPrimitiveDigi
Contains multiple HcalSLHCTriggerPrimitiveSamples with bit-wise information
An HcalSLHCTriggerPrimitiveSample has:
8 bits of “fine grain” – precise usage to be defined
8 bits of “isolated compressed et”
HCAL Upgrade Meeting

5. Upgrade HCAL TP in CMSSW
HcalTriggerPrimitiveDigi
Identified by an HcalTrigTowerDetId
Contains multiple HcalTriggerPrimitiveSamples with bit-wise information
An HcalTriggerPrimitiveSamples has:
8 bits of “compressed et”
1 bit of “fine grain” energy information
HcalSLHCTriggerPrimitiveDigi
Contains multiple HcalSLHCTriggerPrimitiveSamples with bit-wise information
An HcalSLHCTriggerPrimitiveSample has:
8 bits of “fine grain” – precise usage to be defined
8 bits of “isolated compressed et”
HCAL Upgrade Meeting

6. Current TPG Method in CMSSW
Current Compressed ET
All of the ADC values from a trigger tower are converted to linear, integer values
All of these linearized, integer values from a trigger tower are added
For each trigger tower, this sum is converted using a non-linear scale and stored if the non-linear value is high enough
Current Fine Grain
Adds an extra bit of precision
Upgrade Compressed ET
Same as current compressed ET
Upgrade “Isolation” Compressed ET
Same as current compressed ET, but only uses inputs from cells within a range of depths in the trigger tower
Upgrade “Fine Grain”
Currently unassigned: left blank
HCAL Upgrade Meeting

7. Upgrade TPG Method in CMSSW
Current Compressed ET
All of the ADC values from a trigger tower are converted to linear, integer values
All of these linearized, integer values from a trigger tower are added
For each trigger tower, this sum is converted using a non-linear scale and stored if the non-linear value is high enough
Current Fine Grain
Adds an extra bit of precision
Upgrade Compressed ET
Same as current compressed ET
Upgrade “Isolation” Compressed ET
Same as current compressed ET, but only uses inputs from cells within a range of depths in the trigger tower
Upgrade “Fine Grain”
Currently unassigned: left blank
HCAL Upgrade Meeting

8. Linearization methods
Again, trigger primitive compression has two steps
Linearization: Take all cells in a tower, linearize their ADC values for each frame, and add those linearized ADC frames together
Compression: Compress the linearized sum
The linearization step requires LUTs that require non-upgrade HcalDetId's as input. I.e., linearizing cells with high depth values is impossible.
“Hack”: For each HcalDetId within a tower, use instead the HcalDetId with the same subdetector, same ieta, same iphi, and lowest currently-valid depth.
Other methods can be considered too.
Compression seems to work fine.
HCAL Upgrade Meeting

9. Where is this code, and how do I use it?
Jeremy Mans' code is documented on the Twiki:
SLHCSoftware
My code is on the UserCode CVS. Documentation is forthcoming.
UserCode/eberry/Producers/HcalSLHCTrigPr imDigiProducer/
cvs co -d Producers/HcalSLHCTrigPrimDigiProducer UserCode/eberry/Producers/HcalSLHCTrigPr imDigiProducer/
Use on samples produced using Jeremy's release by adding to your cfg.py file:
process.load("Producers.HcalSLHCTrigPrim DigiProducer.hcalSlhcTpDigi_cfi")
process.TPG = cms.Path(process.simHcalSLHCTriggerPrimit iveDigis)
This is a first draft, and documentation will improve
HCAL Upgrade Meeting

10. Plans for the future
In the future, we may want to use a linear compression with an LSB rather than a non- linear compression with LUTs.
Possibly with different LSBs for isolation vs. non- isolation compressed energy.
Discussion now with Sunanda Banerjee on making this part of the standard release in the future.
HCAL Upgrade Meeting